The present invention relates to torsion vibration dampers and in particular, torsion vibration dampers for use as twin mass flywheels in land vehicles.
Known twin mass flywheels include an input flywheel and an output flywheel which can rotate relative to each other about an axis to transmit power from an engine to a transmission and reduce torque fluctuations. Relative rotation of the flywheel masses is resisted by some form of damper means which is speed dependent. Example of such flywheels are disclosed in, for example, the Applicant""s earlier patent GB 2229793B.
It is an object of the present invention to provide a twin mass flywheel which includes an improved form of speed sensitive damper means.
Thus according to the present invention there is provided a twin mass flywheel comprising a first and second flywheel mass which can rotate relative to each other about an axis, the relative rotation being controlled by damper means including one or more connection means in which the centre of gravity of each connection means moves radially with respect to the axis as the first and second flywheel masses rotate relative to each other and the centripetal loads acting on the connection means as the twin mass flywheel rotates tend to bias the first and second flywheel masses towards a pre-determined relative rotational zone.
In a preferred arrangement at least one connection means consists of a mass capable of movement along a first track associated with the first flywheel mass and a torque transmitting connection acting between the mass and the second flywheel mass.
The mass may be capable of movement along a pair of first tracks associated with the first flywheel mass and a torque transmitting connection acting between the mass and the second flywheel mass.
The invention also provides a twin mass flywheel comprising first and second flywheel masses which can rotate relative to each other about an axis, the relative rotation being controlled by one or more connection means in which the centre of gravity of each connection means moves radially with respect to the axis as the first and second flywheel masses rotate relative to each other, the centripetal loads acting on the connection means as the twin mass flywheel rotates tending to bias the first and second flywheel masses towards a pre-determined relative rotational zone, and the or each connection means comprises a mass capable of movement along a first track associated with the first flywheel mass and having a torque transmitting connection acting between the mass and the second flywheel mass via a second track on the second flywheel mass.
The invention further provides a twin mass flywheel comprising a first and second flywheel mass which can rotate relative to each other about an axis, the relative rotation being controlled by one or more connection means in which the centre of gravity of each connection means moves radially with respect to the axis as the first and second flywheel masses rotate relative to each other, the centripetal loads acting on the connection means as the twin mass flywheel rotates tending to bias the first and second flywheel masses towards a pre-determined relative rotational zone, and the or each connection comprises a mass capable of movement along a first track associated with the first flywheel mass and a torque transmitting connection acting between the mass and the second flywheel mass via a link which is pivotally connected at one end to the mass and at the other end to the second flywheel mass.
The invention still further provides a twin mass flywheel comprising a first and second flywheel mass which can rotate relative to each other about an axis, the relative rotation being controlled by one or more connection means in which the centre of gravity of each connection means moves radially with respect to the axis as the first and second flywheel masses rotate relative to each other, the centripetal loads acting on the connection means as the twin mass flywheel rotates tending to bias the first and second flywheel masses towards a pre-determined relative rotational zone, and the or each connection means comprises a mass including a first track along which a follower associated with the first flywheel mass moves and a torque transmitting connection acting between the mass and the second flywheel mass.